Siemens 5SJ6140-7FC Miniature Circuit Breaker, 6kA, 1-pole,

The Siemens 5SJ6140-7FC is a 1-pole miniature circuit breaker rated for 40 A with a C-trip curve and a 6 kA interrupting capacity per IEC 60898. The C-curve (5–10× In) makes it a standard choice for general-purpose branch-circuit protection where moderate inrush — from small motors, lighting ballasts, or control transformers — is expected. The 6 kA breaking capacity covers most commercial and light industrial panelboards fed from a transformer of typical impedance.